Figure 1.

Execution and adaptation. During execution of normal grasping movements, the sensorimotor transformation (f) determines the relation between the visual size of the object (VO) and the maximum grip aperture (MGA). The behavior is presumed to be continually monitored by visual and haptic information. When visual and haptic information about object size are dissociated, any change in f would reflect how the evaluated sensory feedback is weighted. Because of the functional requirements of the task, we expected haptic information to be more heavily weighted when the haptic size of the object increased as compared with when it decreased.